The present invention refers to a filter cartridge for a water tank of a coffee machine, comprising a housing adapted to receive a filter medium and having at least one inlet located at the bottom of the filter cartridge and an outlet located at the bottom of the filter cartridge. A plurality of spaced apart baffle members are located in the interior of the housing and adapted to increase the length of the flow path of the water between the inlet and the outlet.
Such a filter cartridge serves for softening the water contained in the water tank of a coffee machine and used to brew a coffee beverage. As a medium for softening the water, for example a ion exchange resin can be used. As soon as the softening medium is exhausted, i.e. shows less and less softening effect, the filter cartridge should be replaced.